"Please take one or both of the following surveys about tasks that you might do in After Effects. Pretty please? Your doing so will help us to learn what people are having trouble with and how we can make it better."While you're at, if you're interested in Autodesk Smoke or Avid DS, and want to make After Effects into a better DV Rebel-style finishing tool, then make a feature request at the Adobe website.
What's needed for this is an NLE-like realtime playback architecture and more editing features; for more see What Should Adobe Do With Premiere Pro? by Stu Maschwitz. Of course, in the short term Premiere has to be more stable, which is the point of the 64-bit OS rewrite.